Derivative Financial Instruments - Counterparty Credit Quality with Respect to Fair Value of OTC Derivatives Assets (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Derivative Instruments and Hedging Activities Disclosure [Abstract]
A- or higher	$ 173,843
BBB- to BBB	40,565
BB or lower	48,338
Unrated	34,275
Total	$ 297,021

Fair value of OTC derivatives assets, counterparty credit quality A- or higher.

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Fair value of OTC derivatives assets, counterparty credit quality BB or lower.

No definition available.

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Fair value of OTC derivatives assets, counterparty credit quality BBB- to BBB+.

No definition available.

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Fair value of OTC derivatives assets, counterparty credit quality unrated.

No definition available.

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OTC Derivative Assets Included In Financial Instruments Owned.

No definition available.

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No definition available.

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